Implantable tissue connector

ABSTRACT

An implantable tissue connector comprises a conduit and at least one bulge extending outwardly from the conduit&#39;s outer surface in a circumferential direction. At least one blocking ring loosely fitting over the outer surface with a clearance between the outer surface and the blocking ring is provided for mounting tubular living tissue within the clearance. The blocking ring has an inner diameter which is sized relative to an outer diameter of the bulge to prevent the blocking ring from slipping over the bulge when living tissue is mounted within the clearance. During implantation, the conduit is inserted into the tubular part of living tissue and over the bulge. Then, the blocking ring is pushed over the free end of the living tissue against the bulge. The living tissue is secured to the conduit with a self-enhancing effect when the tissue tends to be pulled off of the conduit

BACKGROUND OF THE INVENTION

The present invention relates to an implantable tissue connector that isspecifically adapted to be connected to a tubular part of living tissuewithin a patient's body, such as to the end of the human's large bowelwhen an artificial exit to the large bowel is to be provided. However,the implantable tissue connector of the present invention is not limitedto such application and can be used in connection with many other kindsof tubular living tissue, as will be described in more detail below.

Connecting the end of the human's large bowel to an artificial exit,such as to a fecal excrements collecting container, or connecting ashortened large bowel to the patient's natural intestinal exit hasalways proven difficult and often unreliable. Leakage can occur wherethe connection is not tight over the lifetime. Blood circulation can beprohibited in the end area of the bowel tissue, which can negativelyaffect the muscle functions and peristaltic movement of the bowel andwhich can even lead to starvation of the respective portion of thebowel. Furthermore, the peristaltic movement of the bowel willcontinuously act upon the connection and, thus, the connection can failover time.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide animplantable tissue connector for connecting tubular living tissue in apatient's body, which connection should be reliable over time and notseverely harm the living tissue.

It is a further object to propose different uses for such tissueconnector as well as methods for implanting the tissue connector in apatient's body.

Accordingly, the implantable tissue connector of the present inventioncomprises a conduit with at least a first and a second end and furtherhaving an outer surface.

According to the invention, there are provided special elements forpreventing the tubular tissue from slipping off of the conduit. Moreparticularly, the tissue connector comprises at least one bulgeextending outwardly from the conduit's outer surface in acircumferential direction of the conduit about at least part of theconduit's circumference. Furthermore, at least one blocking ring isloosely fitted over the outer surface of the conduit with a clearancebetween the conduit's outer surface and the blocking ring for mountingliving tissue within said clearance. The blocking ring has an innercross sectional diameter which is smaller than or substantiallyidentical to an outer cross sectional diameter of the at least one bulgeso as to prevent the blocking ring from slipping over the bulge whenliving tissue is mounted within the clearance.

When the tissue connector is implanted in a human being or animal, theliving tissue will be pulled over the conduit's outer surface includingthe bulge. Then the blocking ring will be advanced from the other sideof the bulge over the living tissue towards the bulge such that at leastpart of the living tissue is located intermediate the conduit's outersurface and the blocking ring. This has the effect that, when the tissuetends to slip off of the conduit, it will carry the blocking ringtowards and against the bulge. By this action, the living tissue will becompressed between the bulge and the blocking ring, thereby preventingany further slippage. This effect is self-enhancing with increasingslipping force. As the force tends to decrease again, the compressionforce will decrease accordingly so that blood circulation within theliving tissue will not be negatively affected longer than necessary.Thus, the connection will be reliable over time and not severely harmthe living tissue.

The size of the clearance in a radial direction depends upon theintended use of the tissue connector, i.e. upon the thickness of thetubular living tissue to which the tissue connector is connected.Accordingly, the size may be at average between 0.1 to 0.4 mm, 0.4 to0.8 mm, 0.8 to 1.3 mm, 1.3 to 2 mm, 2 to 3 mm, 3 to 4 mm, 4 to 5 mm,over 5 mm. The clearance should be slightly smaller than the thicknessof the living tissue so as not to severely affect blood circulationwithin the living tissue but nevertheless ensure sufficient frictionalcontact.

While the cross-sectional diameter of the blocking ring shouldpreferably be smaller than the cross-sectional diameter of the bulge, itcan in some instances be identical or even somewhat larger than thisbecause the thickness of the living tissue, even in a compressed state,adds up to the cross-sectional diameter of the bulge so that altogetherthe blocking ring is prevented from slipping over the bulge. Therefore,in case of particularly thick living tissue, the inner cross-sectionaldiameter of the blocking ring may be even somewhat larger than the outercross-sectional diameter of the bulge.

In the regards of materials, both the conduit and the blocking ringshould preferably be made from biocompatible material. This preferablycomprises polymers, such as polytetrafluoroethylene (PTFE), ePTFE,silicone, polyurethane and/or polyetheretherketone (PEEK). However,other materials, such as ceramics and metals, in particular titanium andstainless steel, can be used as well and are preferable for theirstrength.

The conduit can be substantially longer than the particular portion ofthe conduit to which the tubular tissue is connected. In that case, itis preferable that the bulge is located proximately to the respectiveend of the conduit so that the part of the tissue drawn over the conduitis not excessively large. The larger the overlapping part of the tissueis, the larger may become problems of blood circulation within that partof the tissue.

Where the tissue connector is intended to connect two different ends oftubular living tissue material, it may have two of the aforementionedbulges, preferably located proximately to the respective ends of theconduit, with at least one and preferably at least two blocking ringslocated intermediate the two bulges. Of course, more than one blockingring and/or more than one bulge may be provided for each end of theconduit.

In order to facilitate the step of inserting the end or ends of theconduit into the tubular living tissue, it is advantageous to taper thefree end portion of the conduit's end or ends towards the edge of saidfree end portion. Alternatively or in addition, the free end portion maybe provided with a rounded edge. The rounded edge will help to preventany damage to the living tissue when the tissue is pulled over the freeend of the conduit.

As mentioned at the outset, the use of the tissue connector of thepresent invention is not limited to its application at the end of thehuman's large bowel. It can be advantageously used in many otherapplications.

For instance, the tissue connector may be fitted into a human'sesophagus. In this case, the conduit of the tissue connector should havean inner diameter of between 2 and 3.5 cm to provide for a snug fit. Theclearance between the conduit and the blocking ring should be in therange of 2.5 to 5 mm.

Where the tissue connector is connected to a human's trachea, the innerdiameter should be chosen between 1.5 and 2.5 cm, depending upon theposition where at the human's trachea it is to be connected, in order toprovide for a snug fit. The clearance between the conduit and theblocking ring should be in the range of 1 to 2 mm.

Where the tissue connector is fitted into a human stomach, the innerdiameter of the conduit can vary with enlarged boundaries. The clearancebetween the conduit and the blocking ring should be in the range of 3.5to 5 mm.

The tissue connector may also be fitted into a human's gall bladder orits connecting outlet channels. In that case, the conduit should have aninner diameter of between 0.5 and 1.3 cm. The clearance between theconduit and the blocking ring should be in the range of 0.5 to 1.5 mm.

In case that the tissue connector is fitted into a human's small bowel,the inner diameter of the conduit should be between 2 and 3 cm. Theclearance between the conduit and the blocking ring should be in therange of 3 to 4 mm.

In case of the human's large bowel, whose diameter is highlystretchable, the inner diameter of the conduit should be between 3 and5.5 cm to provide for a snug fit. The clearance between the conduit andthe blocking ring should be in the range of 2 to 3.5 mm.

The tissue connector may also be fitted into a human's urethra. In thiscase, the conduit should have an inner diameter of between 0.4 and 0.8cm. The clearance between the conduit and the blocking ring should be inthe range of 0.5 to 1.5 mm.

Also, the tissue connector may be fitted into an human's ureter, inwhich case the inner diameter of the conduit should be chosen between0.4 and 0.7 cm. The clearance between the conduit and the blocking ringshould be in the range of 2 to 4 mm.

The tissue connector may also be connected to the kidney. In order tosnuggly fit it into a human's pelvic part of the kidney, the innerdiameter of the conduit should be in the range of 1 and 5 cm, dependingupon the position where at the human's pelvic it is to be connected. Theclearance between the conduit and the blocking ring should be in therange of 0.5 to 1.5 mm.

The tissue connector may also be fitted into a human's blood vessel. Inthis case, the inner diameter of the conduit should be chosenapproximately similar to the inner diameter of the respective bloodvessel. As an example, the inner diameter may be chosen between 0.1 and0.5 cm in the case of particularly small blood vessels. The tissueconnector may as well be connected to the human's aorta or the heart'satrium or ventricle, in which case the inner diameter of the conduit isin the range of 2 to 3 cm. The clearance between the conduit and theblocking ring should be in the range of 1 to 2 mm.

The tissue connector may also be used as an intermediate piece toreplace a part of tubular living tissue and may as well be used toconnect different types of tubular living tissue, such as where abiological transplant of a third party's body is to be connected to theorgans of a patient.

According to a preferred embodiment of the invention, at least oneflexible sleeve may be mounted on the outer surface of the conduit suchthat it axially extends around at least part of said conduit. Accordingto a first embodiment, the flexible sleeve is initially mounted on saidouter surface either folded or rolled upon itself. According to a secondembodiment, the flexible sleeve is initially mounted on said outersurface so as to be foldable upon itself. According to a third, moregeneral embodiment, the flexible sleeve is not initially mounted on theconduit but will be mounted thereon only at the time of implantation ofthe tissue connector in the patient's body.

The first end of the conduit of the tissue connector is connected to atubular part of living tissue by inserting the first end of the conduitincluding the bulge into the tubular part of living tissue. Where,according to the first embodiment, the flexible sleeve is mounted on theouter surface of the conduit folded or rolled upon itself, the flexiblesleeve is unfolded or unrolled such that at least part of the livingtissue extending over the conduit's outer surface is locatedintermediate the sleeve and the outer surface of the conduit. Where,according to the second embodiment, the flexible sleeve is mounted onthe outer surface of the conduit so as to be foldable upon itself, theflexible sleeve is folded upon itself such that at least part of theliving tissue is located intermediate the folded sleeve or intermediatethe conduit's outer surface and the sleeve. Where, according to thethird embodiment, the flexible sleeve is provided separate from theconduit, the sleeve is advanced over the conduit and the respectiveportion of tubular tissue such that at least part of the living tissueis located intermediate the sleeve and the conduit's outer surface. Ineither of the aforementioned three embodiments, the flexible sleeve mayor may not extend over the bulge.

Either way, the tubular tissue is located somewhere between the conduitand the flexible sleeve and can be held in that position in variousmanners that will be described in the following and that can be appliedindividually as well as in combination.

The advantages achieved with the tissue connector according to theaforementioned three preferred embodiments comprise a good sealing ofthe living tissue between the conduit and the flexible sleeve as well asgood protection of the living tissue by the flexible sleeve. This way,the connection can be made reliable over time while also protecting thetissue against harm.

Where the flexible sleeve overlaps with the living tissue that has beendrawn over the first end of the conduit, it is desirable that theflexible sleeve will exert radial pressure upon the tissue. In instanceswhere strong and/or repeated movement of the tissue material is to beexpected, such as when used as a bowel connector, the radial pressurewill assist in holding the components in place until they are otherwisefixed against one another. In any case, it is preferable to design theflexible sleeve such that the radial pressure is minimal so as not toprohibit the blood circulation in the living tissue.

Furthermore, the conduit should be designed such that it is lessflexible than the flexible sleeve at least in a radial direction so asto provide support to the sleeve against radial forces, in particularagainst the sleeve's aforementioned radial pressure. This way, the openinternal cross section of the conduit will not be affected by the radialforces caused by the flexible sleeve.

Another particularly preferred way of reliably connecting the livingtissue to the tissue connector involves a flexible sleeve that comprisesa porous ingrowth layer allowing ingrowth of living tissue. This willnot only strengthen any connection between the tissue connector and thetissue but will also serve to further seal the connection against anyleakage.

The ingrowth layer should be made from a material that stimulates tissueingrowth. Preferably, the ingrowth layer has a netlike structure thatcan be penetrated by ingrowing tissue, thereby creating a durableconnection between the living tissue and the flexible sleeve. Of course,the ingrowth layer should be made from a biocompatible material, such asDacron®.

Another way of reliably fixing the living tissue to the tissue connectorconsists in suturing the flexible sleeve to the living tissue.Alternatively, the suturing may be performed through the flexible sleeveand an outer wall of the conduit including an interposed portion of theliving tissue. Thereby, the tissue is fixed to both the flexible sleeveand the conduit. Leakage through needle penetrations caused by thesuturing, if any, will automatically close over time by overgrowingtissue material.

It is also possible to perform the suturing through a portion of theliving tissue and the outer wall of the conduit before the flexiblesleeve is placed over the living tissue. This eliminates any problems ofleakage through the penetration holes caused by the suturing as thesleeve will cover and seal such penetration holes.

Preferably, the thread used for suturing is made from a material that isabsorbable by the patient's body. Typically, the thread will be absorbedby the body within about 6 weeks. At that time, however, the tissueingrowth will be sufficiently advanced to compensate for the loss ofstrength that was initially provided by the thread.

Instead or in addition to suturing the flexible sleeve to the conduit bymeans of a preferably absorbable thread, the sleeve may be fixedlyconnected to the conduit along an axially extending portion of thesleeve in any other appropriate way. For instance, the conduit and thesleeve may be bonded along at least part of said axially extendingportion of the sleeve. A primer may be applied on the conduit's outersurface and/or the flexible sleeve to enhance bonding characteristics.

The flexible sleeve may comprise a multi-layer material. This isparticularly advantageous where the flexible sleeve comprises theaforementioned porous ingrowth layer. For instance, the porous ingrowthlayer might itself not be sufficiently stable to be safely handled andpulled over the tubular tissue and/or the porous ingrowth layer mightnot be able to exert the radial pressure onto the tissue. In either ofthese cases, it is advantageous to provide the flexible sleeve with asupport layer for supporting the porous ingrowth layer.

The support layer may be made e.g. from polyurethane or from expandedpolytetrafluoroethylene (ePTFE). ePTFE is particularly preferred as itcan be designed with pores sufficiently large in size so as to allow forthe necessary exchange of particles and/or elements between theunderlying tissue and the surrounding area of the patient's body.Furthermore, the support layer may give better protection to the tissuethan the ingrowth layer.

It is preferable when after implantation the support layer forms anouter layer of the flexible sleeve or, at least, that the ingrowth layerwill be located radial inward from the support layer. Thus, where theflexible sleeve is mounted on the outer surface of the conduit so as tobe foldable up on itself, the ingrowth layer will be located betweenportions of the support layer when the sleeve is folded upon itself.Alternatively, where the flexible sleeve is mounted on the outer surfaceof the conduit folded or rolled upon itself, the ingrowth layer will belocated radial inward from the support layer when the sleeve is unfoldedor unrolled.

Where the tissue connector is intended for connecting with one anothertwo different ends of tubular living tissue, the conduit may have oneflexible sleeve at each of the conduit's first and second ends. Again,the flexible sleeves are preferably located proximately to said firstand second ends.

Of course, it is again preferable to make the flexible sleeve from abiocompatible material, in particular polymer materials similar to thosementioned above in relation to the conduit (except that PEEK would notbe suitable).

The tissue connector may particularly be used and be adapted forconnecting it to at last one of an implantable reservoir, an implantablepump, an implantable motor, an implantable medical device and abiological transplant. The artificial items may even form a part of thetissue connector, either integrally formed therewith or separatelyconnected thereto. The reservoir, pump, motor and/or medical device mayalso be incorporated in the tissue connector between the first andsecond ends of the conduit.

The biological transplant may be any transplant, such as a transplantedheart to be connected by means of the tissue connector to the patient'saorta and/or to other blood vessels (pulmonary arteria etc.).

Instead of being artificial, the aforementioned reservoir may consist ofa biological transplant, but it may as well be made from tissue materialof the patient into whom the reservoir is to be implanted. For instance,the reservoir may be a fecal excrements collecting container, such as aurine bladder or an intestine.

The reservoir may also be a reservoir for medical drugs for thepatient's needs and is preferably adapted to be filled with at least onemedical drug. Such medical drug reservoir may or may not be connected toa medical device, such as an implantable drug delivery device, whichmedical device may additionally include a pump for pumping the drug fromthe reservoir into the patient's body and possibly a motor for the pump.

Any other implantable medical devices may also be connected to theorgans of the patient by means of the tissue connector, with or withouta pump, motor and/or reservoir. Examples of these are an artificialheart, a penile prothesis, an artificial urine bladder, an artificialurethra, an artificial esophagus, an artificial trachea and the like.Examples of biological transplants include a urine bladder, anintestine, a urethra, a ureter, a kidney, a bowel, a heart, anesophagus, a trachea, a blood vessel and the like.

The tissue connector of the present invention can be implanted in ahuman being or animal either in open surgery or by subcutaneous surgery.In either case, the skin will have to be cut before free-dissecting anappropriate location within the patient's body adjacent to the tubularliving tissue and, after the conduit of the tissue connector has beenconnected with one or both ends to the tubular tissue, at least the skinwill have to be sutured at the end of the surgery.

Where the tissue connector is implanted by subcutaneous surgery, thesteps of cutting the skin and free-dissecting the appropriate locationwithin the patient's body comprise the steps of

-   -   inserting a needle-like tube into the patient's body, such as        the patient's thorax or abdomen,    -   filling through said needle gas into the patient's body, i.e.        into the thorax cavity or abdomen cavity,    -   cutting a key-hole,    -   inserting at least one, preferably two, laparoscopic trocars        through the key-hole towards said location,    -   advancing one or more medical instruments and a camera through        the at least one trocar towards said location, i.e. into the        thorax or abdomen, and    -   dissecting an area of the tubular part of living tissue with the        aid of the dissecting tool.    -   The tissue connector may be supplied to said location through        the at least one trocar or through a separate incision.

The invention will now be described in more detail in context with somepreferred embodiments of the invention as shown in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary view of a patient with one tissue connectorconnected to the patient's aorta and another tissue connector connectedto the end of the patient's large bowel.

FIG. 2 shows a cross section of a first embodiment of the tissueconnector in a state connected to living tissue.

FIG. 3 shows a second embodiment of the tissue connector with twoconnecting ends.

FIG. 4 shows a third embodiment of the tissue connector as analternative to the second embodiment.

FIGS. 5 a and 5 b show an alternative for mounting living tissue on afree end of the tissue connector.

FIGS. 6 a and 6 b show another alternative for mounting living tissue ona free end of the tissue connector.

FIGS. 7 a and 7 b show a further alternative for mounting living tissueon a free end of the tissue connector.

FIGS. 8 a and 8 b show a combination of an embodiment similar to the oneshown in FIG. 2 with additional mounting means as shown in FIGS. 5 a and5 b.

FIG. 1 schematically shows a body 100 of a patient with a first tissueconnector 1 connected to the end of the patient's large bowel 50 and asecond tissue connector 1 a interconnecting two pieces of the patient'saorta 60. The tissue connector 1 may either connect the large bowel 50to the patient's anus or to an artificial anus which may include anexcrements collecting container. The tissue connector 1 a may includebetween its two ends a heart valve, a blood pump, a drug delivery deviceor the like.

The tissue connectors 1 and 1 a shown in FIG. 1 represent only a few ofmany different possible locations and applications of the tissueconnector within the human's or, alternatively, an animal's body.Further examples of possible applications have already been outlinedfurther above.

FIG. 2 shows a first embodiment of the tissue connector 1 connected to atubular part of living tissue 80. The tissue connector 1 comprises aconduit 2 with a first end 3 and a second end 4. The second end 4 of theconduit 2 has already been inserted into an end portion of living tissue80. The inner cross section of the conduit 2 is selected toapproximately match the inner cross section of the tubular living tissue80 so as not to obstruct any flow of material. The thickness of the wall5 of the conduit, which is typically circular, is chosen to providesufficient strength so that it does not collapse under the forces thatwill act upon the conduit during use, while providing sufficientflexibility where needed. On the other hand, the thickness should not bechosen too large since the living tissue will have to be stretched overthe outer surface 6 of the conduit 2 without damage and withoutexcessively affecting blood circulation within the end portion 81 of theliving tissue 80.

The wall 5 of conduit 2 is tapered towards its leading edge 7. Inaddition, the leading edge 7 is rounded. These two measures preventdamage to the living tissue 80 when the conduit 2 is inserted into theend portion 81 of the living tissue 80.

The first end 3 may serve and be adapted to be connected to animplantable medical device, an implantable reservoir, an implantablepump, an implantable motor or a combination of the afore mentioned items(generally designated with 200). It may also be connected to any otherimplantable device 200. The implantable device 200 may even form a partof the tissue connector 1, either integrally or attached thereto.

The implantable device 200 may also be a medical device replacing one ormore of the patient's organs, such as an artificial urine bladder, afecal excrement's collecting container, an artificial urethra, anartificial heart, an artificial esophagus, an artificial trachea or thelike. Alternatively, the first end 3 of the conduit 2 may be connectedto a biological implant obtained from a third party's body, such as aurine bladder, an intestine, a urethra, a ureter, a kidney, a bowel, aheart, an esophagus, a trachea, a blood vessel or the like.

The device 200 may also comprise a flow restrictor for partial orcomplete restriction of flow through the conduit. This can be suitablee.g. in the case where the tissue connector is located at the end of thepatient's large bowel.

The device 200 may also be placed between the tissue connector 1 and asecond tissue connector 1 b with conduit 2 b, as is indicated in FIG. 2by dotted lines. This arrangement is practical where the device 200 hasto be placed at a location within one of the patient's organs, such asin a blood vessel, in which case the blood vessel would be divided andthe device 200 placed between the two tissue connectors 1 and 1 bconnected to the respective free ends of the divided blood vessel. As anexample, the device 200 could include a flow restrictor, such as anartificial heart valve, or a drug delivery reservoir.

Apart from the conduit 2 and the optional device 200, the tissueconnector 1 of the embodiment shown in FIG. 2 has a bulge 15 thatextends outwardly from the conduit's outer surface 6 in acircumferential direction of the conduit 2 about at least a part of theconduit's circumference. Furthermore, at least one blocking ring 30loosely fitting over the outer surface 6 of the conduit 2 with aclearance between the outer surface 6 and the blocking ring 30 isprovided for mounting the tubular living tissue 80 within the clearance.The blocking ring has an inner cross-sectional diameter which is aboutthe same as the outer cross-sectional diameter of the bulge 15. Thisprevents the blocking ring from slipping over the bulge when the livingtissue 80, as shown in FIG. 2 , is mounted within the clearance.

When an axial force tends to pull the tubular living tissue 80 from theouter surface 6 of the conduit 2, the blocking ring 30 will move withthe tubular tissue 80, thereby compressing the tubular tissue 80 againstthe bulge 15, so as to prevent any further slippage of the tubulartissue 80 over the bulge 15. This is a self-enhancing effect.Preferably, the blocking ring in this and in the subsequently describedembodiments is made from a material that has a friction coefficient inrelation to living human (outer) mucosa tissue that is higher than afriction coefficient which the conduit's outer surface has in relationto living human (inner) serosa tissue.

FIG. 3 shows a second embodiment of the tissue connector 1 comprisingthe conduit 2 with each of its first and second ends 3 and 4 having acircumferential bulge 15. Between the two bulges 15 two blocking rings30 are arranged. Tubular living tissue 80 has been pulled over theconduit 2 and through the blocking rings 30, and the blocking rings 30have then been pushed into a position closest to the bulges 15.Therefore, when stretching forces are applied to the tubular tissue 80in the one or the other direction, depending upon the direction one ofthe two blocking rings 30 will move towards the associated bulge 15,thereby clamping the tissue 80 between the blocking ring 30 and thebulge 15 and prohibiting any further slippage of the tissue 80 off theconduit 2.

The embodiment shown in FIG. 3 is particularly suitable to strengthenweak sections in a tubular part of living tissue or to seal a poroussection, such as a porous section of the patient's intestine.

The same tissue connector as shown in FIG. 3 may also be used to connecttwo separate ends of tubular tissue or to connect one end of tubulartissue with another end of a hose or the like that may lead e.g. to animplantable medical device or to an exit port, such as an artificialbody exit.

FIG. 4 shows a third embodiment that can be used as an alternative tothe embodiment previously discussed in relation to FIG. 3 . Again, theconduit 2 has two bulges 15 to prevent the tubular tissue 80 fromslipping off of the conduit. However, in this embodiment the bulges 15are arranged in close proximity to one another so that a single blockingring 30 located between the two bulges 15 in an axial direction of theconduit will be sufficient to cooperate with one or the other of the twobulges 15 depending upon the direction of the stretching force actingupon the tissue 80.

FIGS. 5 a and 5 b show an alternative for mounting living tissue on thefree end 3 of the tissue connector 1 to either another part of livingtissue 70 or to a hose. Apart from the conduit 2 and the bulge 15 at thesecond end of the conduit 2, the tissue connector 1 of the embodimentshown in FIG. 5 a has a flexible sleeve 10 axially extending and closelyfitted around a part of the outer surface 6 of the conduit 2. Theflexible sleeve 10 may be delivered separately from the conduit 2 andplaced over the conduit's outer surface 6 shortly before implantationinto the patient's body. However, it is preferred to provide the conduit2 with the flexible sleeve 10 as a unitary item, the flexible sleeve 10preferably fixed to the outer surface 6 by means of bonding, weldingand/or clamping. In the case of bonding, it can be advisable to pretreatthe outer surface 6 e.g. with a primer, depending upon the materialcombination to be bonded together.

In FIG. 5 a , the flexible sleeve 10 is rolled upon itself and can beunrolled over the portion 71 of living tissue 70 so as to cover, sealand protect that portion 71 on the first end 3 of the conduit 2, as isshown in FIG. 5 b . The tissue portion 71 and the overlapping part 11 offlexible sleeve 10 are fixed to the first end 3 of the conduit 2 bysuturing threads 20 therethrough and through the wall 5 of the conduit2, as is indicated in FIG. 5 b by dotted lines.

The flexible sleeve 10 is a multilayer material comprising a porousingrowth layer to allow ingrowth of living tissue. For that, it has anetlike structure. On top of the ingrowth layer 11 there is provided asupport layer 12. The support layer 12 may have one ore more of variousfunctions. One possible function is to provide support to the ingrowthlayer 11 so as to ease handling and/or prevent fussing of the ingrowthlayer. Also, the support layer 12 may provide some tension, therebyexerting a compressive force in a radial direction so as to slightlyclamp the tissue portion 71 against the outer surface 6 of the conduit2. For that, the support layer should have an appropriate elasticity.Finally, the support layer may provide protection for the tissue portion71.

Preferably, the support layer should be porous so that exchange betweenthe tissue portion 71 and the surrounding area within the patient's bodyis possible. This is an important aspect for the ingrowth of livingtissue material into the ingrowth layer 11. Expandedpolytetrafluoroethylene (ePTFE) is particularly suitable, as it isflexible, inert and can be made with any desired porosity. Otherbiocompatible polymers, such as polyurethane and the like, are suitableas well.

FIGS. 6 a and 6 b show an alternative which differs from the connectorshown in FIGS. 5 a and 5 b solely by the fact that the flexible sleeve10 is not rolled upon itself but, instead, folded upon itself. Byunfolding the folded sleeve 10, it can be placed over the tissue portion71 in the same manner as discussed above in relation to FIGS. 5 a, 5 b ,as is shown in FIG. 6 b.

FIGS. 7 a and 7 b show another alternative where the flexible sleeve 10is arranged such that it is foldable upon itself. More particularly, thefirst end 3 of the conduit 2 is inserted in the tissue portion 71 ofliving tissue 70 to an extent that it overlaps a first portion 13 of theflexible sleeve 10. The remaining portion 14 of the flexible sleeve 10not being covered by the tissue portion 71 is rolled upon itself and canbe unrolled so as to cover the tissue portion 71. As a result shown inFIG. 7 b , the flexible sleeve 10 is folded upon itself with the tissueportion 71 placed intermediate the folded sleeve 10.

Different to the alternatives described before, suturing the tissueportion 71 to the wall 5 of the conduit 2 is carried out before thetissue portion 71 is covered with the remaining part 14 of the flexiblesleeve 10. The remaining part 14 thereby seals any penetration holescaused by the suturing.

In an even further alternative, not shown, the first end 3 of theconduit 2 will be inserted in the tissue portion 71 only so far that thetissue portion 71 does not overlap with the flexible sleeve 10. Thus,after unrolling the flexible sleeve 10, only a part of the folded sleeve10 will cover the tissue portion 71.

Furthermore, also not shown, the remaining part 14 of the sleeve 10 isnot necessarily rolled upon itself, as shown in FIG. 7 a , but may layflat against the outer surface 6 of the conduit 2, similar to theembodiment shown in FIG. 6 a.

As will be recognized, the portion 13 of the flexible sleeve 10 isarranged in a circumferential groove provided in the outer surface 6 ofthe conduit 2. It is advantageous when the depth of the groovecorresponds to the thickness of the flexible sleeve 10. This willfacilitate introducing the first end 3 of the conduit 2 into the livingtissue 70.

Any of the described flexible sleeve connections can be combined withthe bulge locking ring locking mechanism. Of these variants, only oneshall exemplary be described in the following in relation to FIGS. 8 aand 8 b . The embodiment shown in FIGS. 8 a and 8 b substantiallycorrespond to the embodiment of FIGS. 5 a and 5 b , where the flexiblesleeve 10 is rolled upon itself and then unrolled to cover the tubulartissue 80 which, in this case, is pulled over the second end 4 of theconduit 2 sufficiently far so as to extend also over the bulge 15. Afterthe flexible sleeve 10 has been unrolled over the tubular tissue 80, theblocking ring 30 is pushed over the flexible sleeve against the bulge15. After a while, the threads 20 sutured to the tubular tissue 80 andthe wall 5 of the conduit 2 (FIG. 8 a ) will have been absorbed by thepatient's body and, about during the same time, living tissue will haveformed in and connect the tubular tissue 80 to the ingrowth layer 11 ofthe flexible sleeve 10. Therefore, as the tubular tissue 80 tends to bepulled off of the second end 4 of the conduit 2, the blocking ring 30will also be moved, press the tubular tissue 80 and the flexible sleeve10 against the bulge 15 and thereby prohibit any further slippage of thetubular tissue 80 over the bulge 15. The friction coefficient betweenthe blocking ring 30 and the outer surface of the flexible sleeve shouldbe higher than the friction coefficient which the conduit's outersurface 6 has in relation to the tubular tissue 80.

Note that the flexible sleeve 10 in its unrolled state as shown in FIG.6 b must not necessarily extend over the bulge 15 but can end a distanceaway from the bulge. In that situation, the blocking ring 30 would notclamp the sleeve 10 against the bulge 15 but only the living tissue 80.

1. An implantable tissue connector adapted so as to be connectable to atubular part of living tissue within a patient's body, comprising aconduit having at least a first end and a second end and further havingan outer surface with at least one bulge extending outwardly from theconduit's outer surface in a circumferential direction of the conduitabout at least a part of the conduit's circumference, and at least oneblocking ring loosely fitting over the outer surface of the conduit witha clearance between the outer surface and the blocking ring for mountingtubular living tissue within the clearance, said blocking ring having aninner cross sectional diameter which is smaller than or substantiallyidentical to an outer cross sectional diameter of the at least one bulgeso as to prevent the blocking ring from slipping over the bulge whenliving tissue is mounted within the clearance, at least one flexiblesleeve adapted to axially extend and closely fit around at least part ofsaid outer surface of the conduit, wherein the at least one flexiblesleeve does not extend over the bulge. 2-102. (canceled)
 103. The tissueconnector of claim 1, wherein the blocking ring is made from a materialthat has a friction coefficient in relation to living human mucosatissue that is higher than a friction coefficient which the conduit'souter surface has in relation to living human serosa tissue.
 104. Thetissue connector of claim 1, wherein the at least one bulge is locatedproximately to said first end of the conduit.
 105. The tissue connectorof claim 1, wherein the conduit has at least two of said bulges with theat least one blocking ring being located intermediate said at least twobulges.
 106. The tissue connector of claim 105, wherein the at least oneblocking ring located intermediate said at least two bulges comprisestwo blocking rings, each of said two blocking rings being locatedproximate one of said at least first and second ends of the conduit.107. The tissue connector of claim 105 or 106, wherein the at least twobulges are each located proximate one of said at least first and secondends of the conduit.
 108. The tissue connector of claim 1,wherein—depending upon the intended use—the clearance is in the range ofone of the following ranges: 0.1 to 0.4 mm, 0.4 to 0.8 mm, 0.8 to 1.3mm, 1.3 to 2 mm, 2 to 3 mm, 3 to 4 mm, 4 to 5 mm, over 5 mm.
 109. Thetissue connector of claim 1, wherein the flexible sleeve is made from abiocompatible material, which preferably comprises at least one polymerselected from the following group of polymers comprising:polytetrafluoroethylene, silicone, polyurethane, expandedpolytetrafluoroethylene (ePTFE).
 110. The tissue connector of claim 1,wherein the conduit is less flexible than the flexible sleeve at leastin a radial direction so as to provide support to the sleeve againstradial forces.
 111. The tissue connector of claim 1, wherein theflexible sleeve comprises a multilayer material.
 112. The tissueconnector of claim 1, wherein the conduit and the flexible sleeve arefixedly connected to each other along an axially extending portion ofthe sleeve, preferably the conduit and the flexible sleeve are bondedalong at least part of said axially extending portion of the sleeve.113. The tissue connector of claim 1, wherein the at least one flexiblesleeve is located proximately to said first end of the conduit.
 114. Thetissue connector of claim 1, wherein the conduit has at least two ofsaid flexible sleeves, preferably the at least two flexible sleeves areeach located proximately to one of said at least first and second endsof the conduit.
 115. The tissue connector of claim 1, wherein the firstend of the conduit has a free end portion and tapers towards the edge ofsaid free end portion.
 116. The tissue connector of claim 1, wherein thefirst end of the conduit has a free end portion with a rounded edge.117. The tissue connector of claim 1, wherein said second end of theconduit is adapted for connecting the tissue connector to at least oneof the following items: an implantable reservoir, an implantable pump,an implantable motor, an implantable medical device, a biologicaltransplant.
 118. The tissue connector of claim 1, wherein between thefirst and second ends of the conduit or connected to the second end ofthe conduit, there is provided at least one of the following items: areservoir, a pump, a motor, a medical device, preferably the reservoiris artificial or a biological transplant or made from tissue material ofa patient into whom the reservoir is to be implanted.
 119. The tissueconnector of claim 1, comprising a flow restrictor for partial orcomplete restriction of flow through the conduit.
 120. The tissueconnector of claim 1, wherein the conduit has an inner diameter ofbetween 0.1 and 0.5 cm or 1 and 2 cm or 2 and 3 cm or 3 and 4 cm or 4 cmand over.
 121. The tissue connector of claim 1, wherein said conduit issized so as to be snuggly fitted into a human's esophagus, a human'strachea, a human's stomach, a human's gall bladder or its connectingoutlet channels, a human's small bowel, a human's large bowel, a human'surethra, a human's ureter, a human's pelvic part of the kidney or ahuman's blood vessel.